A skipped cam sprocket tooth may toss the camshaft out of time by 20 degrees. Racing can timing 2-4 degrees is a radical movement. Sometimes 1 degree will change a camshaft's characteristics significantly.
The distributor gear is held in place by a roll pin. The hole goes through the collar of the gear passes through the distributor shaft and out the other side.
The pin shears. But seldom cleanly. There is an ugly spur of metal sticking out. That spur of metal can delay but not prevent Armageddon. The gear slips a little. Leaving the distributor BEHIND a seemingly more politically correct term than RETARDED. Slip, pull over, advance timing, slip, twist further, twist twist twist. Corkscrew that distributor until it yanks all the sparkplug wires loose. Eventually the spur gets bored and takes it's ball and goes home. Wheeeeee! The gear spins as loose as a goose.
WARNING! WARNING WILL ROBINSON! DANGER!
That gear can slip off the distributor shaft now that the burr has been worn to zip. Pull distributor, gear says "---- ---" and stays behind. You are going to need a STRONG magnet with a flexible 24" shaft sitting beside you be-FORE you even think about pulling that distributor. I like the idea of getting ahold of a STRONG NEODYMIUM MAGNET. I mean one strong magnet like those yanked from computer hard discs. This does not eliminate the need for that 24" flexible magnet.
Remove distributor cap
CLANK!!! goes the NEODYMIUM magnet atop the vacuum advance wings.
Now remove the hold down bolt. And steel yourself.
With the hands of a surgeon lift the distributor up. it may stick to the camshaft a little. Be prepared. But the cam is slightly less magnetic than the distributor and the gear.
Do not knock that danged gear loose as it passes up through the hole in the block.
Misery: is fishing for the dropped gear with the flexible magnet
Agony: is not finding it.
